Apparatus and method for handling an integrated circuit

ABSTRACT

An apparatus and method are provided for picking up an integrated circuit and for facilitating the optical testing thereof. The apparatus comprises a pick-up mechanism that includes a vacuum chamber. The vacuum chamber is defined by an upper portion, an expandable member, and a lower portion. The lower portion defines a suction orifice that is moveable with a movement of the expandable member. An optical pathway is defined by the vacuum chamber, the optical pathway passing through the suction orifice and onto an integrated circuit that is held against the suction orifice via a vacuum pressure applied to the vacuum chamber.

TECHNICAL FIELD

The present invention is generally related to the field of integratedcircuit fabrication and, more particularly, is related to an apparatusand method for the automated handling and testing of optical integratedcircuits.

BACKGROUND OF THE INVENTION

The electronics industry currently produces thousands of integratedcircuits each day. These circuits have come down in cost significantlyin more recent years due to the use of effective mass productiontechniques that facilitate the current high output. The machineryemployed in these mass production techniques is quite complex and oftenperforms repetitive tasks. Such machinery is typically engineered formaximum reliability over a large number of operation cycles, whateverthe specific operation may entail.

In addition to the use of automated machines to produce variousintegrated circuits, industry also employs automated machines to testthe integrated circuits to ensure maximum reliability and quality of theend product. Due to the high volumes created, such testing equipment isdesigned with the goal in mind to operate with maximum efficiency overnumerous cycles without failure. However, some testing systems fallshort of this goal.

For example, in testing one particular type of integrated circuit,namely, an active pixel sensor, machines are employed to pick up thesensor and place it on a test circuit such that the leads of the sensorcome into contact with electrical pads through which the sensor may betested. Such sensors require that light be applied to their lightsensitive surface to determine whether the response of the sensor iswithin acceptable parameters.

However, typical pick-up devices employed to handle such sensors do notprovide an ability to both hold the sensor and apply light to the lightsensitive surface. In particular, suction cups that are typically usedin such handling equipment generally cover the light sensitive surfacesand a proper test may not be performed when such handlers place thesensor against the appropriate test pads.

To solve this problem, some have attempted to use suction devices thatallow light to illuminate the light sensitive surfaces. However, suchmachinery has proven unreliable. In particular, such pick-up machinescannot effectively create a reliable vacuum seal with the integratedcircuit that allows light to be applied to the light sensitive surfacesover an acceptable number of testing cycles.

SUMMARY OF THE INVENTION

In light of the foregoing, the present invention provides an apparatusand method for picking up an integrated circuit that facilitates opticaltesting thereof. Briefly described, the apparatus comprises a pick-upmechanism that includes a vacuum chamber. The vacuum chamber is definedby an upper portion, an expandable member, and a lower portion. Thelower portion defines a suction orifice that is moveable with a movementof the expandable member. An optical pathway is defined by the vacuumchamber, the optical pathway passing through the suction orifice andonto an integrated circuit that is held against the suction orifice viaa vacuum pressure applied to the vacuum chamber.

During operation, the suction orifice is applied to a surface of theintegrated circuit and the vacuum is applied to the vacuum chamber,thereby applying a suction hold to the integrated circuit. Theexpandable member contracts, thereby moving the suction orifice in anaxial direction until the integrated circuit comes into contact with anumber of contact edges that stop the movement. The expandable membermay be, for example, a bellows or other similar device as an integralportion of the vacuum chamber.

The present invention can also be viewed as providing a method forpicking up and testing an integrated circuit. In this regard, the methodcan be broadly summarized by the following steps: providing a vacuumchamber having an upper portion, an expandable member, and a lowerportion, the lower portion defining a suction orifice, the suctionorifice being moveable with a movement of the expandable member;applying the suction orifice to a smooth face of an integrated circuit;evacuating the vacuum chamber to pick up the integrated circuit; andilluminating the smooth face of the integrated circuit with a light thatpropagates along an optical pathway that passes through the suctionorifice.

The present invention has numerous advantages, including the movement ofthe suction orifice that accommodates the use of a more rigid O-ringthat provides greater durability and reliability in operation. Themovement of the suction orifice also allows the pick-up mechanism to beemployed with integrated circuits of varying height with the lessdurable O-ring. In addition, due to the flexibility of the O-ring andthe fact that it is frictionally mounted into the O-ring groove, it iseasily replaced by hand when worn, etc. Also, the frictional mounting ofthe O-ring keeps it in place in the O-ring groove and it does not moveinto the optical pathway in any way. In addition, the pick-up mechanismallows the automated testing of active pixel sensors, for example, byapplying light to the sensor while it is held by the pick-up mechanismwhich places the sensor over test pads for testing. Also, the over alldesign of the pick-up mechanism is simple, user friendly, robust andreliable in operation, efficient in operation, and easily implementedfor mass commercial production.

Other features and advantages of the present invention will becomeapparent to one with skill in the art upon examination of the followingdrawings and detailed description. It is intended that all suchadditional features and advantages be included herein within the scopeof the present invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings. The components in the drawings are not necessarily to scale,emphasis instead being placed upon clearly illustrating the principlesof the present invention. Moreover, in the drawings, like referencenumerals designate corresponding parts throughout the several views.

FIG. 1 is a section view of a pick-up mechanism according to anembodiment of the present invention;

FIG. 2 is a section view of the pick-up mechanism of FIG. 1 engaging anintegrated circuit;

FIG. 3A is a top view of a upper portion employed in the pick-upmechanism of FIG. 1;

FIG. 3B is a side view of the upper portion of FIG. 3A;

FIG. 4A is a bottom view of a lower portion employed in the pick-upmechanism of FIG. 1;

FIG. 4B is a side view of the lower portion of FIG. 4A;

FIG. 5A is a top view of an O-ring employed in the pick-up mechanism ofFIG. 1; and

FIG. 5B is a side view of the O-ring of FIG. SA.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, shown is a pick-up mechanism 100 according toan embodiment of the present invention. The pick-up mechanism 100includes a support bracket 103 that provides a support structure for themajor components of the pick-up mechanism 100. The pick-up mechanism 100also includes a vacuum chamber 105 that is defined by an upper portion106 top, an expandable member 109, and a lower portion 113. The upperportion 106 may comprise, for example, a top flange or other suitablestructural member. The expandable portion 109 may comprise, for example,a bellows or other suitable member that expands and contractsaccordingly. Also, the lower portion 113 may comprise, for example, apick-up flange or other suitable structural member.

The upper portion 106 is set into the support bracket 103 as shown andis held into place by set screw 116. The support bracket 103 alsoincludes a vacuum inlet 119 that provides access to a threaded vacuuminlet 123 of the upper portion 106. An appropriate vacuum fitting 126 isthreaded into the threaded vacuum inlet 123 through the vacuum inlet 119of the support bracket 103 as shown. The expandable member 109 isadhesively attached to the bottom of the upper portion 106 and the topof the lower portion 113 as shown.

The pick-up mechanism 100 also includes a mating flange 129 that isremovably attached to the bottom of the support bracket 103 via one of anumber of means, for example, by bolts, etc. The mating flange 129restricts the movement of the lower portion 113 in an axial direction131. In particular, the lower portion 113 is movable within the matingflange 129 with the movement, i.e., the expansion and/or thecontraction, of the expandable member 109. The mating flange 129restricts the movement of the lower portion 113 in the axial direction131. The mating flange 129 also includes a number of contact edges 133that together define an integrated circuit stop as will be discussed.

The pick-up mechanism 100 flier includes a lens/glass diffuser 136 thatis seated into the upper portion 106 and adhesively mounted thereto. Theexpandable member 109 is adhesively mounted to the bottom of the upperportion 106. Both the lens/glass diffuser 136 and the expandable member109 are attached to the upper portion 106 sing a suitable adhesive toprevent any vacuum leakage as will be discussed.

The lower portion 113 is also adhesively attached to the expandablemember 109 as shown. The bottom of the lower portion 113 defines asuction orifice 139. The suction orifice 139 is exposed at its exit face143. The lower portion 113 also includes an O-ring groove 146 that isplaced around the perimeter of the exit face 143 of the suction orifice139. Mounted in the O-ring groove 146 is an O-ring 153. The O-ring 153is preferably frictionally mounted into the O-ring groove 146 to providefor easy removal and replacement by hand. The O-ring 153 defines aceiling junction with an integrated circuit 156 that may include, forexample, active pixel sensor circuits.

The vacuum chamber 105 generally defines an optical pathway 159 thatpasses through the lens/glass diffuser 136, the upper portion 106,expandable member 109, and the lower portion 113 and exits out of thesuction orifice 139. The optical pathway 159 advantageously facilitatesan optical testing of the integrated circuit 156 while it is held by thepick-up mechanism 100 as will be discussed.

With reference to FIG. 2, the operation of the pick-up mechanism 100 isdiscussed. To begin, the pick-up mechanism 100 is positioned above, forexample, an optical integrated circuit 156 or other integrated circuitthat is to be tested. The suction orifice 139 is then placed against theupper surface of the integrated circuit 156 such that the O-ring 153 ismated against the upper surface of the integrated circuit 156.Thereafter, a vacuum pressure is applied to the vacuum inlet 126,causing the lower portion 113 with the integrated circuit 156 to bepulled upward in an axial motion.

The axial movement occurs when the expandable member 109 contracts asshown. The O-ring 153 advantageously creates a vacuum seal with theupper surface of the integrated circuit 156 and therefore the integratedcircuit is held against the lower portion 113. Together the lowerportion 113 and the integrated circuit 156 will move upward until thecontact edges 133 come into contact with the leads 163 of the integratedcircuit 156. Although two contact edges 133 are shown, it is understoodthat there may be four contact edges 133 that come into contact withleads 163 that extend from the integrated circuit 156 on all four sides,etc. The integrated circuit 156 is thus seated against the contact edges133 thereby preventing the further axial movement of the lower portion113 and the integrated circuit 156.

Thereafter, the pick-up mechanism 100 travels to a new position to placethe integrated circuit 156 on contact pads for testing as is known inthe art. A light source 166 may then be employed to generate light thatpropagates along the optical pathway 159 and falls on the sensor 156.The light source 166 may comprise, for example, a laser, incoherentlight, or other suitable light source. Light sensitive components 169located on the surface of the integrated circuit 156 sense the light andthe testing of the integrated circuit 156 is performed. The lightsensitive components 169 may be covered by a layer of transparentmaterial, such as glass, etc. Thus, the integrated circuit 156 maycomprise, for example, an active pixel sensor or other similarintegrated circuit. The integrated circuit 156 is released by relievingthe vacuum at the vacuum inlet 126.

The pick-up mechanism 100 provides several benefits including an axialmovement of the suction orifice 139 that accommodates the use of a morerigid O-ring 153. The axial movement allows the pick-up mechanism 100 tobe employed with integrated circuits 156 of varying height and at thesame time allows the use of the O-ring 153. In particular, the use ofthe expandable member 109 allows the suction orifice 139 along with theO-ring 153 to be placed over integrated circuits with greater height asthe lower portion 113 will be pushed up into the mating flange 129, theexpandable member 109 contracting accordingly.

In addition, due to the material makeup of the O-ring 153, it can lastthrough thousands of pick-up cycles and is easily replaced by hand.Also, the O-ring 153 stays in place in the O-ring groove 146 and doesnot block the optical pathway 159 in any way. Thus, the pick-upmechanism 100 facilitates the automated testing of active pixel sensors,for example, by applying light to the sensor while it is held by thepick-up mechanism 100 which places the sensor over test pads fortesting.

The materials that are used to manufacture the support bracket 103,upper portion 106, and the lower portion 113 may be, for example,aluminum, steel, or other material. Aluminum or other lightweightmaterials are preferable as the resulting pick-up mechanism 100 requiresless force and energy to manipulate during use, etc. The expandablemember 109 may comprise stainless steel or other suitable material thatis durable and can withstand repeated use without degradation ordeveloping holes, etc.

With reference to FIGS. 3A AND 3B, shown are side and top views of theupper portion 106. The upper portion 106 facilitates adhesive mountingof the lens/glass diffuser 136 therein. Specifically, a silicon adhesivemay be applied to a contact surface 173 of the upper portion 106 or tothe lens/glass diffuser 136. Thereafter, the lens/glass diffuser 136 isplaced into position in the upper portion 106. The upper portion 106also includes spill over grooves 176 that accommodate a run over ofsilicon adhesive. After placing the lens/glass diffuser 136 into theupper portion 106, it is given a quarter turn, for example, to ensure aproper vacuum seal is formed between the lens/glass diffuser 136 and theupper portion 106.

With reference to FIGS. 4A AND 4B, shown are top and side views of thelower portion 113 according to another embodiment of the presentinvention. The lower portion 113 includes interior angled surfaces 179.The interior angled surfaces 179 serve to prevent the light propagatingalong the optical pathway 159 (FIG. 2) from reflecting off of theinterior angled surfaces 179 thereby adversely affecting the uniformityof the light that falls on the light sensitive components 169 (FIG. 2).Rather than fall on the light sensitive components 169, the reflectedlight propagates toward the opposing interior angled surfaces 179. Theangle of the interior angled surfaces 179 with respect to the opticalpathway 159 is, for example, 20 degrees, but other angles may beemployed. Also, the interior angled surfaces 179 as well as the entireinterior of the lower portion 113 are preferably colored in anon-reflective color such as, for example, flat black to reduce unwantedreflection of the light that propagates along the optical pathway 159.

The O-ring groove 146 located around the suction orifice 139 preferablyaccommodates the frictional mounting of the O-ring 153 therein. TheO-ring groove 146 may appear in many different shapes and sizes,depending upon the particular size and shape of the integrated circuit156 that one wishes to pick up with the pick-up mechanism 100. Due tothe fact that the O-ring 153 is made of a flexible material, the O-ringcan typically be fitted into the O-ring groove 146 even though theO-ring groove 146 is a different shape than the O-ring 153.

The O-ring groove 146 also includes a surface smoothness that isnecessary to form a vacuum seal between the O-ring 153 and the lowerportion 113. For best results, the roughness/height index value of thesurface of the O-ring groove 146 is generally not greater than 16microinches, for example, although other smoothness factors may beemployed providing that a proper vacuum seal is formed. Alternatively,the O-ring may be mounted into the O-ring groove 146 using anappropriate adhesive, etc., however such a mounting may make the O-ring153 harder to remove.

Finally, with reference to FIGS. 5A AND 5B, shown are side and top viewsof the O-ring 153. The O-ring 153 is comprised of a material ofsufficient hardness to prevent the integrated circuit 156 (FIG. 1) fromsticking to the O-ring 153 itself after the vacuum is relieved in thevacuum chamber 104 (FIG. 1). The material of the O-ring 153 is alsopreferably durability and capable of withstanding harsh atmospheres. Forexample, the O-ring 153 may be exposed to solvents such as acetone oralcohol in the typical integrated circuit manufacturing environment andshould not experience any significant degradation therefrom. Onesuitable material that may be used for the O-ring 153, for example, isViton, manufactured by and commercially available from Pressure Seals,Inc., of South Windsor, Connecticut although other suitable materialsmay be employed as well keeping the above criterion in mind. Manyvariations and modifications may be made to the above-describedembodiment(s) of the invention without departing substantially from thespirit and principles of the invention. All such modifications andvariations are intended to be included herein within the scope of thepresent invention.

What is claimed is:
 1. An apparatus for picking up an integratedcircuit, comprising: a vacuum chamber having an expandable member and asuction orifice, the suction orifice being moveable with an expansionand a contraction of the expandable member; an optical pathway definedby the vacuum chamber, the optical pathway passing through the suctionorifice; a vacuum chamber cover affixed to the vacuum chamber and havingan aperture aligned with the optical pathway; and an aperture coveragemeans, the aperture coverage means configured to permit the passage oflight therethrough, whereby the integrated circuit can be lifted byengaging the suction orifice and establishing the vacuum in the vacuumchamber therewith and whereby light propagating along the opticalpathway falls on the integated circuit so that the integrated circuitmay be tested.
 2. The apparatus of claim 1, wherein the expandablemember further comprises a bellows.
 3. The apparatus of claim 1, furthercomprising an O-ring mounted around a perimeter of an exit face of thesuction orifice, the O-ring defining a sealing junction that is appliedto the integrated circuit.
 4. The apparatus of claim 3, furthercomprising an O-ring groove around the perimeter of the suction orifice,the O-ring being frictionally mounted in the O-ring groove.
 5. Theapparatus of claim 3, wherein the O-ring is comprised of a material ofsufficient hardness to prevent a sticking of the integrated circuit tothe O-ring.
 6. The apparatus of claim 3, wherein the O-ring is comprisedof viton material.
 7. The apparatus of claim 4, wherein the O-ringgroove is defined by a smooth groove surface, the smooth groove surfaceforming a seal with the O-ring.
 8. The apparatus of claim 4, wherein theO-ring groove is rectangular in shape, wherein the O-ring is fitted intothe O-ring groove.
 9. The apparatus of claim 7, wherein the smoothgroove surface of the O-ring groove has a roughness-height index valuenot greater than 16 microinches.
 10. A method for picking up anintegrated circuit, comprising the steps of: providing a vacuum chamberhaving expandable member and a suction orifice, the suction orificebeing moveable with an expansion and a contraction of the expandablemember; providing a vacuum chamber cover affixed to the vacuum chamberand having an aperture aligned with an optical pathway; providing anaperture coverage means, the aperture coverage means configured topermit the passage of light therethrough; applying the suction orificeto a smooth face of an integrated circuit; evacuating the vacuum chamberto pick up the integrated circuit; and illuminating the smooth face ofthe integrated circuit with a light that propagates along the opticalpathway that passes through the suction orifice.
 11. The method of claim10, wherein the step of evacuating the vacuum chamber to pick up theintegrated circuit further comprises the step of moving the integratedcircuit in an axial direction until the integrated circuit is heldagainst an integrated circuit stop.
 12. The method of claim 10, whereinthe step of evacuating the vacuum chamber to pick up the integratedcircuit further comprises the step of contracting the expandable member,thereby causing a movement of the integrated circuit in the axialdirection.
 13. The method of claim 10, further comprising the step offrictionally mounting an O-ring in an O-ring groove around the perimeterof the suction orifice.
 14. The method of claim 13, further comprisingthe step of preventing a sticking of the integrated circuit to theO-ring by providing an O-ring comprised of a material of a sufficienthardness where the integrated circuit does not adhere thereto.
 15. Themethod of claim 13, further comprising the step of preventing a stickingof the integrated circuit to the O-ring by providing an O-ring comprisedof a viton material.
 16. The method of claim 13, further comprising thestep of sealing a junction between the O-ring and the O-ring groove witha smooth groove surface.
 17. The method of claim 13, further comprisingthe step of fitting the O-ring into the O-ring groove, where the O-ringgroove is rectangular in shape.
 18. The method of claim 16, furthercomprising the step of providing a roughness-height index value notgreater than 16 microinches in the smooth groove surface.
 19. Anapparatus for picking up and testing an integrated circuit, comprising:a light source, the light source generating light suitable for testingthe integrated circuit; a vacuum chamber having an expandable member, anaperture and a suction orifice, the suction orifice being moveable withan expansion and a contraction of the expandable member; an opticalpathway defined by the vacuum chamber, the optical pathway passingthrough the suction orifice; and a lens affixed to the vacuum chamberaperture such that a vacuum applied to the vacuum chamber is maintained,and aligned with the optical pathway such that light generated by thelight source passes through the lens and propagates along the opticalpathway, whereby the integrated circuit is held by the apparatus byengaging the suction orifice with the integrated circuit andestablishing the vacuum in the vacuum chamber, and whereby lightpropagating along the optical pathway falls on the integrated circuit.20. The apparatus of claim 19, further comprising a plurality of contactedges, each one of the contact edges affixed to the expandable membersuch that when the expandable member is expanded, each one of thecontact edges contacts at least one of a plurality of pins on theintegrated circuit.
 21. The apparatus of claim 19, the vacuum chamberfurther comprising a plurality of interior angled surfaces configuredsuch that a portion of light propagating along the optical pathway isreflected away from the integrated circuit so that light falling on theintegrated circuit is uniform.
 22. The apparatus of claim 21, theplurality of interior angled surfaces further comprising anon-reflective color surface such that the portion of light reflectedaway from the integrated circuit is minimized.
 23. The apparatus ofclaim 22, wherein the non-reflective color surface is a flat blackcolor.